The overall goal is to determine whether coronary artery bypass surgery (CABG) is superior to percutaneous transluminal coronary angioplasty (PTCA) for the treatment of multivessel coronary artery disease in patients with severe angina. Patients with anatomy suitable for revascularization by either modality will be entered into a data registry, and approached for randomization within several pre-defined subgroups (unstable angina, age greater than 70, poor left ventricular function, prior bypass surgery). Randomization will result in assignment either to PTCA or to CABG, and the assigned revascularization procedure will be performed within 2 weeks of randomization. Long-term safety and efficacy of the two techniques will be compared using 3 major endpoints: 1) freedom from major cardiac event (cardiac or sudden death, non-fatal myocardial infarction, repeat revascularization procedure, rehospitalization greater than or equal to 5 days for unstable angina), quality of life score (angina, cardiac medication used, exercise capacity), and 3) net economic cost over the 4 year follow-up period. Scheduled follow-up catheterization will be performed at 4 years to assess patency of the revascularization intervention. In addition to the above endpoints, efforts will be made to define anatomic subsets most amenable to successful PTCA, and to evaluate the comparative efficacy of "complete" revascularization of all lesions greater than or equal to 70% diameter reduction versus "incomplete" revascularization of only one or more "culprit" lesions. All data will be accumulated in a data registry to define the current status of these two revascularization methods. Given the widespread nature of coronary artery disease, the expense associated with bypass surgery, and the potential that PTCA may be able to provide comparable benefit at lower economic cost, it is vitally important to perform such a randomized clinical trial at this time. This proposal seeks participation of the applicant institution as one of several clinical centers participating in the design, execution, and analysis of this trial.